The overhead depends on the instrumentation that you put into your app. It consists of:
All three factors mainly depend on the number of nodes that your instrumentation is about to produce.
For example: a User Action PurePath shows that an action consists of 10 nodes: a root node and 9 subnodes.
Creating user actions consumes time as well, on average 6 milliseconds per node on Androidand 12 milliseconds per node on iOS. This is the time that we add to a user action.
Normal user actions consist of less than 10 nodes per action, so overhead should be less than in this example.